Yoon Sorah, Armstrong Brian, Habib Nagy, Rossi John J
Department of Molecular and Cellular Biology, Beckman Research Institute of City of Hope, Duarte, California.
Light Microscopy Core, City of Hope, Duarte, California.
Mol Cancer Res. 2017 Jul;15(7):811-820. doi: 10.1158/1541-7786.MCR-16-0462. Epub 2017 Apr 10.
Identifying targets that are exposed on the plasma membrane of tumor cells, but expressed internally in normal cells, is a fundamental issue for improving the specificity and efficacy of anticancer therpeutics. Using blind cell Systemic Evolution of Ligands by EXponetial enrichment (SELEX), which is untargeted SELEX, we have identified an aptamer, P15, which specifically bound to the human pancreatic adenocarcinoma cells. To identify the aptamer binding plasma membrane protein, liquid chromatography tandem mass spectrometry (LC-MS/MS) was used. The results of this unbiased proteomic mass spectrometry approach identified the target of P15 as the intermediate filament vimentin, biomarker of epithelial-mesenchymal transition (EMT), which is an intracellular protein but is specifically expressed on the plasma membrane of cancer cells. As EMT plays a pivotal role to transit cancer cells to invasive cells, tumor cell metastasis assays were performed P15-treated pancreatic cancer cells showed the significant inhibition of tumor metastasis. To investigate the downstream effects of P15, EMT-related gene expression analysis was performed to identify differently expressed genes (DEG). Among five DEGs, P15-treated cells showed the downregulated expression of matrix metallopeptidase 3 (MMP3), which is involved in cancer invasion. These results, for the first time, demonstrate that P15 binding to cell surface vimentin inhibits the tumor cell invasion and is associated with reduced MMP3 expression. Thus, suggesting that P15 has potential as an anti-metastatic therapy in pancreatic cancer. This study reveals that anti-vimentin RNA aptamers selected via blind-SELEX inhibit the tumor cell metastasis. .
识别在肿瘤细胞质膜上暴露但在正常细胞内表达的靶点,是提高抗癌治疗特异性和疗效的一个基本问题。我们使用了非靶向的指数富集配体系统进化(SELEX)即盲筛细胞SELEX,鉴定出一种适体P15,它能特异性结合人胰腺腺癌细胞。为了鉴定与适体结合的质膜蛋白,我们使用了液相色谱串联质谱(LC-MS/MS)。这种无偏向性蛋白质组质谱方法的结果确定P15的靶点为中间丝波形蛋白,它是上皮-间质转化(EMT)的生物标志物,是一种细胞内蛋白,但在癌细胞质膜上特异性表达。由于EMT在将癌细胞转变为侵袭性细胞过程中起关键作用,因此进行了肿瘤细胞转移实验。用P15处理的胰腺癌细胞显示出肿瘤转移受到显著抑制。为了研究P15的下游效应,进行了EMT相关基因表达分析以鉴定差异表达基因(DEG)。在五个DEG中,用P15处理的细胞显示基质金属肽酶3(MMP3)的表达下调,MMP3参与癌症侵袭。这些结果首次证明,P15与细胞表面波形蛋白的结合抑制了肿瘤细胞侵袭,并与MMP3表达降低有关。因此,表明P15在胰腺癌中具有作为抗转移治疗的潜力。这项研究表明,通过盲筛SELEX选择的抗波形蛋白RNA适体可抑制肿瘤细胞转移。